Eco-friendly decolorization method of jeans

ABSTRACT

Provided is an eco-friendly decolorization method of jeans including: a fabric input step of putting denim fabric into a decolorizing device; an ozone gas injecting step of injecting ozone gas into the decolorizing device in which denim fabric is put; and a purified water spraying step of spraying purified water to the denim fabric through a sprayer disposed in the decolorizing device filled with ozone gas through the ozone gas injecting step. The eco-friendly decolorization method of jeans can decolorize naturally and uniformly, and remarkably reduce generation of wastewater by using ozone and water, thereby providing an eco-friendly effect.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an eco-friendly decolorization method of jeans, and more specifically, to an eco-friendly decolorization method of jeans, which can decolorize naturally and uniformly, and remarkably reduce generation of wastewater by using ozone and water, thereby providing an eco-friendly effect.

Background Art

The term of ‘jeans’ is a common name of pants, which are manufactured with fabric obtained by applying blue (indigo) dyes, such as indigo blue, to denim fabric woven very densely. Jeans are very hard, strong, and practical, and are excellent at design so that all people patronize jeans.

Meanwhile, like other fashion clothes, jeans are manufactured in various types and forms while changing their forms and colors according to consumers' tastes. The jeans are very durable and strong, but have a very stretchy texture at the early stage of wearing. So, there are many cases that consumers, manufacturers or merchants wear or sell jeans after intentionally wearing out manufactured jeans through sand blasting or stone washing.

The most frequently used method among methods for decolorizing jeans is a method of putting jeans on a tube, injecting air into the tube to expand the jeans, and spraying a decolorizing liquid, such as a potassium permanganate liquid, with a spray gun.

However, the method of spraying the decolorizing liquid with the air spray gun has several disadvantages in that it is difficult to produce constant products and a failure rate is high since the method of spraying the decolorizing liquid with the air spray gun is mainly used when only a portion is decolorized since the decolorizing liquid is not uniformly sprayed on the entire jeans, and since the form of decolorization or conditions of products may be varied according to the spraying liquid and the spraying range while an operator sprays the decolorizing liquid with the air spray gun.

In addition, in the conventional decolorization method, stones or rubber balls for decolorization are frequently put in a decolorizing device together with the decolorizing liquid. Since the stones or the rubber balls for decolorization are pulverized during use, they must be replaced periodically. Moreover, since wastes are generated through the pulverization and lots of water is consumed in order to remove foreign matters or the decolorizing liquid during or after decolorization, it is not eco-friendly since a great deal of wastewater is generated, and efficiency in manufacturing process is deteriorated and manufacturing costs are increased excessively since post-processing for wastewater treatment must be performed.

PATENT LITERATURE Patent Documents

Patent Document 1: Korean Patent Laid-open No. 10-2001-0090305 (Oct. 18, 2001)

Patent Document 2: Korean Patent No. 10-0417813 (Jan. 27, 2004)

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made in view of the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide an eco-friendly decolorization method of jeans, which can decolorize naturally and uniformly, and remarkably reduce generation of wastewater by using ozone and water, thereby providing an eco-friendly effect.

To accomplish the above object, according to the present invention, there is provided an eco-friendly decolorization method of jeans including: a fabric input step of putting denim fabric into a decolorizing device; an ozone gas injecting step of injecting ozone gas into the decolorizing device in which denim fabric is put; and a purified water spraying step of spraying purified water to the denim fabric through a sprayer disposed in the decolorizing device filled with ozone gas through the ozone gas injecting step.

According to an embodiment of the present invention, the decolorizing device includes: a chamber having a sealed inside and a door disposed at the front to be sealably opened and closed; a perforated drum mounted inside the chamber to rotate around a shaft and accommodating articles to be decolorized; first and second water spray nozzles fixed inside the perforated drum and respectively located at right and left sides of the upper portion around the shaft of the perforated drum; an ozone gas inlet connected with an ozone generator to put ozone gas into the chamber; and an outlet for discharging the ozone gas in the chamber to the outside.

According to an embodiment of the present invention, in the ozone gas injection step, 400 g to 700 g of ozone per hour is injected.

According to an embodiment of the present invention, in the purified water spraying step, 2 L to 3 L of purified water is sprayed to the denim fabric for 3 minutes to 30 minutes through spray nozzles disposed in the decolorizing device filled with ozone gas through the ozone gas injection step.

According to an embodiment of the present invention, the purified water is sprayed into a nano-particle size.

The eco-friendly decolorization method of jeans according to the present invention can decolorize naturally and uniformly, and remarkably reduce generation of wastewater by using ozone and water, thereby providing an eco-friendly effect.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention in conjunction with the accompanying drawings, in which:

FIG. 1 is a flow chart illustrating an eco-friendly decolorization method of jeans according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view schematically illustrating a decolorizing device used in the decolorization method according to the present invention.

FIG. 3 is a photograph showing the appearance of the decolorized jeans prepared through Examples 1 to 2 and a Comparative Example 1 of the present invention.

FIG. 4 shows images of jeans manufactured by Example 3 and Comparative Examples 2 and 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, preferred embodiments and physical properties of components of the present invention will be described in detail with reference to the accompanying drawings. However, such embodiments of the present invention are to describe the present invention in detail such that those skilled in the art can implement the present invention easily, and the technical idea and scope of the present invention are not limited to the embodiments described herein.

An eco-friendly decolorization method of jeans according to an embodiment of the present invention includes: a fabric input step S101 of putting denim fabric into a decolorizing device; an ozone gas injecting step S103 of injecting ozone gas into the decolorizing device in which denim fabric is put; and a purified water spraying step S105 of spraying purified water to the denim fabric through a sprayer disposed in the decolorizing device filled with ozone gas through the ozone gas injecting step S103.

The fabric input step S101 is to put the denim fabric into the decolorizing device. As illustrated in FIG. 2 , the decolorizing device includes: a chamber 10 having a sealed inside and a door (not shown) disposed at the front to be sealably opened and closed; a perforated drum 20 mounted inside the chamber 10 to rotate around a shaft and accommodating articles to be decolorized; first and second water spray nozzles 21 and 22 fixed inside the perforated drum 20 and respectively located at right and left sides of the upper portion around the shaft of the perforated drum 20; an ozone gas inlet 12 connected with an ozone generator to put ozone gas into the chamber 10; and an outlet 11 for discharging the ozone gas in the chamber 10 to the outside.

In this instance, it is preferable that the perforated drum 20 has volume capable of accommodating 50 to 100 pairs of jeans at once. The decolorizing device uniformly mix the articles to be decolorized inside the perforated drum 20 when the perforated drum 20 repeats reciprocating after the articles to be decolorized are put in the perforated drum 20, puts ozone into the chamber 10 through the ozone gas inlet 12, and at the same time, performs decolorization of the articles to be decolorized by spraying water through the first and second water spray nozzles 21 and 22.

In this instance, as illustrated in FIG. 2 , the decolorizing device maximizes decolorization efficiency by spraying water using the second water spray nozzle 22 located at a position opposed to the articles to be decolorized when the articles to be decolorized are located at a position of the solid line of FIG. 2 and by spraying water using the first water spray nozzle 21 located at a position opposed to the articles to be decolorized when the articles to be decolorized are located at a position of the virtual line of FIG. 2 .

In more detail, as illustrated in FIG. 2 , when the perforated drum 20 rotates so that the articles to be decolorized are located at the solid line, water is sprayed from the second water spray nozzle 22 by a sensor disposed on a rotary shaft of the perforated drum 20, and water is sprayed from the first water spray nozzle 21 by a sensor disposed on the rotary shaft of the perforated drum 20 when the perforated drum 20 rotates in the opposite direction so that the articles to be decolorized is located on the virtual line. Therefore, the decolorizing device blocks water from being sprayed to a position where the articles to be decolorized do not exist so as to maximize decolorization efficiency.

The ozone gas injection step S103 is a step of injecting ozone gas to the decolorizing device in which the denim fabric is put through the fabric input step S101. 400 g to 700 g of ozone gas per hour is injected into the chamber 10 through the ozone gas inlet 12 connected to the chamber 10 disposed in the decolorizing device in which 50 to 100 pairs of denim fabric is put through the fabric input step S101.

After the ozone gas injection step S103, when the chamber 10 of the decolorizing device is filled with ozone gas and purified water is sprayed through the purified water spraying step S105, the purified water on which ozone is stuck is coated on the surface of the denim fabric, and decolorization is carried out.

That is, when the ozone gas is injected through the ozone gas injection step S103 and the purified water are sprayed through the purified water spraying step S105, ozone treatment water is generated, and the generated ozone treatment water is stuck to the surface of jeans so as to carry out a decolorization process.

In this instance, if an injection amount of ozone gas is less than 400 g per hour, the decolorization effect of jeans is deteriorated. If the injection amount of ozone gas exceeds 700 g per hour, the decolorization effect is not improved significantly, but treatment costs are increased due to injection of the excessive amount of ozone gas.

The purified water spraying step S105 is a step of spraying purified water to the denim fabric through the first and second water spray nozzles 21 and 22 disposed in the decolorizing device filled with ozone gas through the ozone gas injection step S103. When the chamber 10 of the decolorizing device is filled with ozone gas through the ozone gas injection step S103, 2 L to 3 L of purified water is sprayed to the denim fabric for 3 minutes to 30 minutes through the first and second water spray nozzles 21 and 22, which are fixed inside the perforated drum 20 mounted to rotate around the shaft in the chamber 10 and are respectively located at right and left sides of the upper portion around the shaft of the perforated drum 20.

In this instance, the first and second water spray nozzles may respectively have nano-pattern nozzles attached to head portions thereof so that the purified water can be sprayed into the size of nanoparticles.

The nano-pattern nozzle may have a porous layer of a nano unit formed by oxidation of anodic aluminum oxide (AAO) or a porous layer of a nano unit formed by focused ion beam irradiation, or a porous layer of a nano unit formed by a nano-imprint method.

The anodic aluminum oxide (AAO) oxidation process is a method of forcibly oxidizing using electricity. In general, an oxidized layer is formed on the surface of aluminum by forced oxidation in order to prevent rust from being formed on an aluminum window. With development of measurement technology, it has been known that the oxidation pattern has the porous layer of nano unit, and so, it is used in nano technology. When the anodic oxidation process layer is usually made using oxalic acid, pores are formed at intervals of about 100 nm. The nano-pattern nozzle can be manufactured by maintaining or closing a perforated state to form a specific pattern using the anodic oxidation process nano-mask.

In addition, the focused ion beam (FIB) method is to accelerate focus of Ga+ ion beams at high voltage (30 keV) so that the Ga+ ion beams collide against the surface of a sample, in which a nozzle hole will be made, to remove the surface material. In this instance, the material removed from the surface is in the form of a secondary ion or a neutral atom.

Furthermore, the nano-imprint method is a technique suggested to realize nano-processing which is ultra-fine processing. Thermoplastic resin or photopolymer resin is coated on a substrate to manufacture a nano-sized mold using E-beam, and then, pressure is applied to the mold to transcribe a pattern on the resin. An etching process is applied to remove remaining resin layers, thereby manufacturing a nano-pattern nozzle.

When the purified water of a nano size is sprayed through the first and second water spray nozzles 21 and 22 having the nano-pattern nozzles, a specific surface area of water is remarkably improved and an area in contact with the surface of jeans is increased, thereby improving decolorization effect of jeans and providing uniform decolorization level.

Hereinafter, the eco-friendly decolorization method of jeans according to the present invention and physical properties of the jeans decolorized by the decolorization method will be described.

EXAMPLE 1

100 sheets (50 kg) of denim fabric for women, which is treated with cat sand and washed in a washing liquid containing 500 L of water, 1 kg of a boisterous agent, and 1 kg of enzyme at temperature of 60° C. for 20 minutes, was washed, dehydrated, and dried in 600 L of water at room temperature for ten minutes, and then, was put in the decolorizing device. After that, ozone of 500 g was injected per hour, 2 L of water was sprayed and decolorized for 20 minutes. The decolorized denim was washed in 600 L of water for 15 minutes, and was dehydrated. After that, the dehydrated denim was dried at 100° C. for 40 minutes to manufacture decolorized jeans.

EXAMPLE 2

Example 2 was carried out in the same way as the Example 1, except that 3 L of water was sprayed for 30 minutes to manufacture decolorized jeans.

EXAMPLE 3

100 sheets (50 kg) of denim fabric for women, which is treated with cat sand and washed in a washing liquid containing 500 L of water, 1 kg of a boisterous agent, and 1 kg of enzyme at temperature of 60° C. for 20 minutes, was washed and dehydrated in 600 L of water at room temperature for ten minutes, and then, was put in a dryer to dry at temperature of 100° C. for 50 minutes. After that, the denim was put into the decolorizing device, ozone of 500 g was injected per hour, and 2.5 L of water was sprayed for ten minutes to manufacture decolorized jeans.

Comparative Example 1

100 sheets (50 kg) of denim fabric for women, which is treated with cat sand and washed in a washing liquid containing 500L of water, 1 kg of a boisterous agent, and 1 kg of enzyme at temperature of 60° C. for 20 minutes, was washed in 600 L of water at room temperature for ten minutes. After washing, the denim was washed in a stone washing liquid in which 75 Kg of floatstones was mixed in 500 L of water for 30 minutes. The washed denim was washed in 600 L of water at room temperature for ten minutes, After dehydration, the denim was dried at temperature of 100° C. for 40 minutes, and potassium permanganate aqueous solution having a mass concentration of 1.5% was sprayed to the dried denim for 20 seconds to decolorize. The decolorized denim was neutralized in a neutralizing solution, in which 1.05 L of hydrogen peroxide and 0.45 L of glacial acetic acid were added to 500 L of water, at temperature of 60° C. for 15 minutes. The neutralized denim was washed in 500 L of water for 10 minutes, and the washed denim was put in a decolorizing liquid, in which 4 L of sodium hypochlorite was mixed with 500 L of water, at temperature of 60° C. for 20 minutes to be decolorized. The decolorized denim was neutralized in a neutralizing solution in which 4 kg of hyposulfite was mixed with 600 L of water. The neutralized denim was washed in 600 L of water for 15 minutes. After dehydration, the denim was dried at 100° C. for 40 minutes to manufacture decolorized jeans.

Comparative Example 2

100 sheets (50 kg) of denim fabric for women, which is treated with cat sand and washed in a washing liquid containing 500L of water, 1 kg of a boisterous agent, and 1 kg of enzyme at temperature of 60° C. for 20 minutes, was washed in 600 L of water at room temperature for ten minutes. After dehydration, the denim was dried at temperature of 100° C. for 50 minutes. The dried denim was put in the decolorizing device together with wet cloths cut into pieces, wherein the wet cloths and water were mixed at a weight ratio of 1:1, and then, ozone of 500 g per hour was injected for ten minutes to manufacture decolorized jeans.

Comparative Example 3

100 sheets (50 kg) of denim fabric for women, which is treated with cat sand and washed in a washing liquid containing 500 L of water, 1 kg of a boisterous agent, and 1 kg of enzyme at temperature of 60° C. for 20 minutes, was washed in 600 L of water at room temperature for ten minutes. After dehydration, the denim was dried at temperature of 100° C. for 50 minutes. The dried denim was put in the decolorizing device, and then, ozone of 500 g per hour was injected for ten minutes to manufacture decolorized jeans.

The amount of water consumed during the jean decolorization process carried out through the Examples 1 and 2 and the Comparative Example 1 is shown in the following Table 1.

TABLE 1 Water Use of Division consumption (L) chemicals Example 1 1720 X Example 2 1730 X Comparative Example 1 4900 ◯

As shown in Table 1, the decolorization processes of jeans carried out through Examples 1 to 2 of the present invention are eco-friendly since the amount of consumed water is remarkably reduced compared to the decolorization process of Comparative Example 1, and do not use chemicals.

In addition, FIG. 3 shows images of jeans manufactured by Examples 1 to 2 and Comparative Example 1.

As shown in FIG. 3 , jeans manufactured through Examples 1 to 2 of the present invention made little difference in a faded level or a color sense from jeans manufactured through Comparative Example 1.

Moreover, FIG. 4 shows images of jeans manufactured by Example 3 and Comparative Examples 2 and 3.

As shown in FIG. 4 , jeans manufactured through Example 3 of the present invention shows decolorization effect superior to jeans manufactured through Comparative Examples 2 and 3.

Therefore, the eco-friendly decolorization method of jeans according to the present invention can decolorize naturally and uniformly, and remarkably reduce generation of wastewater by using ozone and water, thereby providing an eco-friendly effect.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes and modifications may be made therein without departing from the technical idea and scope of the present invention and such changes and modifications belong to the claims of the present invention. 

What is claimed is:
 1. An eco-friendly decolorization method of jeans comprising: a fabric input step of putting denim fabric into a decolorizing device; an ozone gas injecting step of injecting ozone gas into the decolorizing device in which denim fabric is put; and a purified water spraying step of spraying purified water to the denim fabric through a sprayer disposed in the decolorizing device filled with ozone gas through the ozone gas injecting step.
 2. The eco-friendly decolorization method according to claim 1, wherein the decolorizing device comprises: a chamber having a sealed inside and a door disposed at the front to be sealably opened and closed; a perforated drum mounted inside the chamber to rotate around a shaft and accommodating articles to be decolorized; first and second water spray nozzles fixed inside the perforated drum and respectively located at right and left sides of the upper portion around the shaft of the perforated drum; an ozone gas inlet connected with an ozone generator to put ozone gas into the chamber; and an outlet for discharging the ozone gas in the chamber to the outside.
 3. The eco-friendly decolorization method according to claim 1, wherein in the ozone gas injection step, 400 g to 700 g of ozone per hour is injected.
 4. The eco-friendly decolorization method according to claim 1, wherein in the purified water spraying step, 2 L to 3 L of purified water is sprayed to the denim fabric for 3 minutes to 30 minutes through spray nozzles disposed in the decolorizing device filled with ozone gas through the ozone gas injection step.
 5. The eco-friendly decolorization method according to claim 4, wherein the purified water is sprayed into a nano-particle size. 